#include<string>
#include<vector>
#include <list>
#include<iostream>
#include<stdio.h>
using namespace std;

int main() {
    int N;
scanf("%d",&N);
int X[N];
int Y[N];
for(int i =0;i<N;i++){
    int x;
    int y;
    scanf("%d",&x);
    scanf("%d",&y);
    X[i] = x;
    Y[i] = y;
}
bool issegment = true;
bool issegment2 = true;
int curr = X[0];
int curr1 = Y[0];
for(int i =1;i<N;i++){
  if(curr == X[i] && issegment) {
      issegment = true;
  }
  else {
    issegment = false;
  }
   if(curr1 == Y[i] && issegment2) {
      issegment2 = true;
  }
  else {
    issegment2 = false;
  }
        }


if(issegment || issegment2) {
    cout << "YES";
}
else {
    cout << "NO";
}
return 0;
}